Graphene-based heating coating, method of manufacture and use in heating appliances

Abstract

The application relates to the field of electrothermal materials, and provides a graphene-based heating coating and a preparation method thereof.The coating is prepared from functionalized graphene, surface-modified bismuth telluride nanobelt, polyaniline, bisphenol A epoxy acrylate, polyurethane acrylate, a dispersing agent, a leveling agent, a silane coupling agent, a defoaming agent and a propylene glycol methyl ether acetate / N-methyl pyrrolidone mixed solvent.Functionalized graphene is modified by hyperbranched polyolefin-acryl-POSS copolymer, and is obtained through ultrasonic peeling, centrifugal separation, gradient washing and vacuum drying; the surface-modified bismuth telluride nanobelt is modified by an amino silane coupling agent to improve the interface compatibility.The preparation method comprises the steps of solvent premixing, nanofiller dispersion, ultrasonic homogenization, coupling agent modification, ultraviolet light curing and thermal curing.The heating coating has high conductivity, excellent thermal stability and adhesion, and can be widely applied to heating electrical appliances and intelligent temperature control equipment.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrothermal materials, in particular to a graphene-based heating coating, a preparation method and application in heating appliances. BACKGROUND

[0002] In modern intelligent heating equipment and industrial thermal management systems, high-efficiency and stable heating elements play a crucial role in improving energy utilization efficiency, optimizing equipment performance and prolonging service life. Graphene, as a two-dimensional carbon material with excellent electrical and thermal conductivity, has shown great potential in applications such as flexible heating films, electrothermal plates, and intelligent temperature control devices. However, to meet the practical application requirements of heating appliances, the heating coating not only needs to have high-efficiency electrothermal conversion performance, i.e., to achieve uniform and rapid temperature response at a lower voltage, but also needs to have excellent adhesion to ensure that the coating exists stably on different substrate surfaces (such as metal, ceramic or polymer substrates) for a long time without peeling or cracking. In addition, the coating also needs to have good high-temperature resistance and environmental stability to adapt to complex working environments, such as long-term reliable operation under high temperature, high humidity or frequent thermal cycling conditions. Therefore, developing a graphene-based heating coating with high electrothermal conversion efficiency, excellent adhesion and long-term environmental stability not only can improve the overall performance of the heating element, but also can broaden its application range in smart home, medical care, aerospace and industrial automation fields, which has important significance for promoting the development of high-efficiency thermal management technology.

[0003] Currently, the research on graphene-based heating coating has made certain progress, but there are still deficiencies in electrothermal performance and adhesion. For example, Chinese Patent No. CN112920704B discloses an electric heating coating paint, an electric heating skin and an anti-icing and snowing system. The coating realizes electrothermal conversion through the excellent electrical conductivity of graphene, but its electrothermal efficiency is low, and the uniformity of the coating and the heat response speed still need to be improved, resulting in local overheating or uneven heating. In addition, due to the lack of effective interfacial bonding force between graphene and most substrates, the coating is prone to peeling, cracking or adhesion loss during long-term use, especially under high temperature or thermal cycling conditions. The main reason for these deficiencies is that the dispersibility of graphene in the solvent system is limited, resulting in uneven internal structure of the coating, and the existing adhesive or functionalization means cannot effectively enhance the chemical bonding force between graphene and the substrate, resulting in poor mechanical stability of the coating. Therefore, how to optimize the dispersion state of graphene, improve the electrothermal conversion efficiency of the coating and enhance the interfacial bonding force has become a key problem to be solved in the current research on graphene-based heating coating. SUMMARY

[0004] (1) Technical problems solved

[0005] The application aims to provide a graphene-based heating coating, a preparation method and application on a heating appliance, and solve the problems of insufficient electric heating performance and adhesion of the graphene-based heating coating.

[0006] (2) Technical scheme

[0007] To achieve the above-mentioned purpose, the application provides the following technical scheme:

[0008] A graphene-based heating coating is prepared from the following raw materials in parts by weight: functionalized graphene 3-12 parts, surface-modified bismuth telluride nanobelt 2.5-4.5 parts, polyaniline 2-8 parts, bisphenol A epoxy acrylate 12-35 parts, polyurethane acrylate 5-15 parts, benzoin diethyl ether 0.5-1.5 parts, BYK-220S dispersant 0.5-2.0 parts, HY-F-3777 fluorocarbon modified leveling agent 0.3-0.8 parts, silane coupling agent kh560 1.0-2.5 parts, silicone emulsion defoaming agent 0.2-0.5 parts, and propylene glycol methyl ether acetate / N-methyl pyrrolidone mixed solvent 25-40 parts.

[0009] The functionalized graphene is prepared by mixing hyperbranched polyolefin-acryl-POSS copolymer and graphene oxide in chloroform solvent, ultrasonic stripping, centrifugal separation, vacuum filtration, gradient washing and vacuum drying.

[0010] The hyperbranched polyolefin-acryl-POSS copolymer is prepared by catalytic polymerization, solvent precipitation, filtration and vacuum drying of acrylic cage polysilsesquioxane, 1,4-butanediol diacrylate and anhydrous dichloromethane in a Schlenk reaction system.

[0011] The surface-modified bismuth telluride nanobelt is prepared by ultrasonic dispersion of bismuth telluride nanobelt in deionized water, surface modification with 3-aminopropyltriethoxysilane, magnetic stirring, centrifugal separation, deionized water washing and vacuum drying.

[0012] Further, the preparation method of the functionalized graphene is as follows: taking hyperbranched polyolefin-acryl-POSS copolymer and graphene oxide as raw materials, mixing 80-100 mL of chloroform solvent in a mass ratio of 1:(4-6) to form a mixed system, placing the mixed system in an ultrasonic treatment device, controlling the ultrasonic power to be 280-320 W, the treatment time to be 25-35 min, and the treatment temperature to be 20-30℃, then transferring the mixed system after ultrasonic treatment to a centrifuge, centrifuging at a speed of 3800-6500 rpm for 40-50 min, removing the unpeeled aggregates, collecting the supernatant to obtain a graphene primary dispersion liquid, vacuum filtering the graphene primary dispersion liquid through a polytetrafluoroethylene filter membrane with a pore size of 90-110 nm, gradient washing the filter membrane surface sediment with chloroform solvent, adding 45-55 mL of solvent each time and washing at a stirring speed of 300-500 rpm for 3-6 min, repeating the washing for 3-5 times, drying the purified functionalized graphene powder in a vacuum environment at 35-65℃ for 10-26 h, and obtaining the functionalized graphene.

[0013] Further, the preparation method of the hyperbranched polyolefin-acryl-POSS copolymer is as follows: taking 100 parts of acrylic cage polysilsesquioxane, 12.0-16.0 parts of 1,4-butanediol diacrylate, and 90-110 parts of anhydrous dichloromethane into a Schlenk reaction bottle, controlling the system temperature to be 25-35℃, mixing at a stirring speed of 300-500 rpm for 30-40 min to form a homogeneous solution, then dissolving 2.2-2.8 parts of α-diimine palladium in 40-60 parts of anhydrous dichloromethane, injecting the homogeneous solution through a syringe pump at a rate of 0.5-1.0 mL / min, maintaining the ethylene pressure to be 0.08-0.12 MPa, and continuously stirring and polymerizing at 28-32℃ for 22-26 h, after the reaction is completed, removing the solvent by nitrogen blowing, obtaining a preliminary product, then dissolving the preliminary product in 220-280 parts of tetrahydrofuran, adding 750-1250 parts of methanol drop by drop for precipitation, washing the filter cake with 250-500 parts of methanol for 2-3 times after vacuum filtration, redissolving the product in 150-250 parts of tetrahydrofuran, adding 500-1000 parts of acetone for secondary precipitation, and vacuum drying at 20-30℃ for 70-74 h to obtain the hyperbranched polyolefin-acryl-POSS copolymer.

[0014] The design of the present application of hyperbranched polyolefin-acryl-POSS copolymer functionalized graphene oxide is mainly used for enhancing the dispersion stability, interfacial bonding force and electro-thermal performance of graphene-based materials. By introducing the hyperbranched polyolefin-acryl-POSS copolymer, its unique hyperbranched structure provides abundant functional groups, which can form strong interaction with graphene oxide, thereby effectively improving the dispersibility of graphene in the solvent system and improving the uniformity of graphene in the composite system. In addition, the presence of the acryl-POSS part endows the material with high chemical stability and thermal stability, so that the functionalized graphene can still maintain excellent electrical conductivity in high temperature environment. Through the steps of ultrasonic peeling, centrifugal separation and gradient washing, the unreacted aggregates and impurities can be efficiently removed, ensuring that the obtained functionalized graphene has high purity and excellent sheet structure, thereby further optimizing its electro-thermal conversion efficiency. In the preparation process, the synthesis of hyperbranched polyolefin-acryl-POSS copolymer adopts Schlenk reaction system, and through the steps of ethylene polymerization and solvent precipitation, a hyperbranched polymer with good solubility is obtained, which can effectively combine with graphene oxide and promote the peeling of graphene oxide, increase the interlayer spacing and specific surface area of graphene, and thereby enhance the interfacial compatibility of graphene in the coating system. In addition, chloroform as a solvent can provide a suitable polar environment, which is helpful for the uniform adsorption of hyperbranched polyolefin-acryl-POSS copolymer on the surface of graphene oxide, realizing the effective modification of graphene. Finally, through the vacuum drying process, the residual solvent is removed to obtain stable functionalized graphene powder, which not only has excellent dispersion stability and interfacial bonding force, but also can effectively improve the conductive network structure of graphene in subsequent coating applications, thereby improving the electro-thermal conversion efficiency and long-term stability of the overall coating.

[0015] Further, the preparation method of the surface-modified bismuth telluride nanobelt is as follows: 100 parts of bismuth telluride nanobelt is weighed by weight fraction, 200-500 parts of deionized water is added, and a uniform suspension is formed under the condition of ultrasonic power of 100-300 W and frequency of 35-40 kHz for 30-60 min; 5-20 parts of 3-aminopropyl triethoxysilane is added in the suspension, and stirred at a magnetic stirring rate of 300-400 rpm for 1-3 h; after the reaction is completed, the suspension is centrifuged at 3000-8000 rpm for 10-20 min for solid-liquid separation, and the separated solid is washed with 50-100 parts of deionized water repeatedly for 2-3 times, each time at a stirring rate of 200-400 rpm for 5-10 min; finally, the solid is placed in a vacuum drying oven and dried at a temperature of 60-100°C and a vacuum degree of-0.08 to-0.10 MPa for 6-12 h to obtain the surface-modified bismuth telluride nanobelt.

[0016] Further, the preparation method of the bismuth telluride nanobelt is as follows: 9.5-10.5 mmol of bismuth chloride dihydrate, 14.5-15.5 mmol of tellurium powder, 78-82 mmol of potassium hydroxide and 29-31 mmol of potassium borohydride are mixed and then transferred to a polytetrafluoroethylene-lined high-pressure reaction kettle, N,N-dimethylformamide is injected into the reaction kettle to form a precursor suspension at 85-95 wt.%, the sealed reaction kettle is placed in a programmed oven, heated to 100-180 ℃ at a heating rate of 2-5 ℃ / min and kept at a constant temperature for 10-20 h, then naturally cooled to 25-35 ℃ at a rate of 0.5-2.0 ℃ / min, after the reaction kettle is opened, the reaction mixture is filtered under a vacuum degree of -0.08 to -0.10 MPa through a Buchner funnel, washed with 50-100 mL of deionized water repeatedly for 3-5 times, and then washed with 30-50 mL of anhydrous ethanol repeatedly for 2-3 times, finally, the product is dried at a temperature of 75-85 ℃ and a vacuum degree of -0.08 to -0.10 MPa for 8-12 h, and finally the bismuth telluride nanobelt is obtained.

[0017] Further, the average width of the bismuth telluride nanobelt is 20-50 nm, and the average length is 1-10 μm.

[0018] The design of the amino silane surface modification of bismuth telluride nanobelt is mainly used for enhancing the interface compatibility and dispersion stability of the material. As a functional filler, the bismuth telluride nanobelt has wide potential in conductive and thermal management applications due to its excellent thermoelectric performance, but its low surface activity and easy agglomeration limit its uniform distribution and interface bonding capacity in the composite system. Through the introduction of aminopropyl triethoxysilane, a stable organic silane layer can be formed on the surface of the bismuth telluride nanobelt, which not only improves the dispersibility of the nanobelt, but also enhances its bonding force with the matrix resin or other fillers. During the ultrasonic dispersion process, the bismuth telluride nanobelt forms a uniform suspension system in a deionized water medium, and then the physical adsorption and chemical bonding of the amino silane and the nanobelt surface are promoted through magnetic stirring, ensuring the uniformity and stability of the modified layer. After centrifugal separation and multiple washing, the unreacted silane and impurities can be effectively removed, improving the purity of the modified material. Finally, through the vacuum drying process, the residual water and solvent are removed, so that the surface modified bismuth telluride nanobelt has good storage stability and application adaptability. In addition, the synthesis of the bismuth telluride nanobelt adopts a solvent thermal reaction of bismuth chloride dihydrate, tellurium powder, potassium hydroxide and potassium borohydride in a high-pressure reaction kettle, and the introduction of N,N-dimethylformamide provides a good dissolution environment for the reaction system, which is helpful for the formation and growth of the bismuth telluride nanobelt. By optimizing the heating rate and constant temperature reaction time, the size and morphology of the nanobelt can be controlled to ensure its stability in the subsequent modification and composite system. After cooling, suction filtration and multiple washing, the obtained bismuth telluride nanobelt can be further purified, and dried under suitable temperature and vacuum conditions to obtain a nanobelt structure with high crystallinity and good dispersibility. Overall, through reasonable synthesis and modification strategies, the bismuth telluride nanobelt not only maintains excellent thermoelectric performance, but also significantly improves its stability in solvents and composite matrix, and enhances its interface bonding capacity with other functional materials, thereby improving the overall performance and practicality of the composite system.

[0019] Further, the propylene glycol methyl ether acetate / N-methyl pyrrolidone mixed solvent is a mixture of propylene glycol methyl ether acetate and N-methyl pyrrolidone in a volume ratio of (30-45):(55-70).

[0020] The application further discloses a preparation method of the graphene-based heating coating.

[0021] S1. Add propylene glycol methyl ether acetate / N-methyl pyrrolidone mixed solvent, BYK-220S dispersant and silicone emulsion defoaming agent into a stirring kettle, pre-mix for 10-20 min at a stirring rate of 200-400 rpm, control the system temperature to maintain 25±5℃, then add functionalized graphene and surface modified bismuth telluride nanobelt, increase the stirring rate to 800-1200 rpm and continue for 30-60 min to form a primary dispersion slurry;

[0022] S2. Add polyaniline, bisphenol A epoxy acrylate and polyurethane acrylate into the primary dispersion slurry in sequence, process for 30-60 min under the power of 100-300 W and the frequency of 20-40 kHz by using an ultrasonic probe, control the viscosity of the slurry to 2000-4000 mPa·s at room temperature, continue to add silane coupling agent KH560, and react for 60-120 min under the stirring rate of 500-800 rpm under nitrogen protection to form a uniform composite slurry;

[0023] S3. Add benzene diethyl ether and HY-F-3777 fluorocarbon modified leveling agent into the composite slurry, mix for 20-40 min under the stirring rate of 300-500 rpm in the dark, filter on line through a microfiltration membrane with a pore size of 1-5 μm to remove aggregates to obtain a final coating slurry;

[0024] S4. Coating the coating slurry on the surface of a substrate, transfer to an ultraviolet curing device, irradiate for 3-8 min under the condition of a wavelength of 365 nm, a light intensity of 50-100 mW / cm², control the substrate temperature to 45-60℃, then post-cure for 10-30 min in a hot air circulation oven at 80-100℃ to form a graphene-based heating coating.

[0025] The application also discloses an application of the graphene-based heating coating in a heating electric appliance.

[0026] This invention employs a multi-component synergistic dispersion and UV curing process, primarily designed to enhance the conductivity, adhesion, and uniformity of graphene-based heat-cured coatings. The introduction of a propylene glycol methyl ether acetate / N-methylpyrrolidone mixed solvent provides a favorable dissolution environment for the coating system, ensuring uniform dispersion of functionalized graphene and surface-modified bismuth telluride nanoribbons. Furthermore, the use of BYK-220S dispersant further reduces the risk of filler agglomeration and improves dispersion stability. Simultaneously, the addition of an organosilicon emulsion defoamer effectively controls the bubble content of the system, preventing bubbles from affecting film quality during coating curing. By gradually increasing the stirring rate, the functionalized graphene and surface-modified bismuth telluride nanoribbons are fully dispersed under high shear conditions, forming a stable primary dispersion slurry. In subsequent steps, polyaniline, bisphenol A epoxy acrylate, and polyurethane acrylate are added sequentially. Ultrasonic probing promotes uniform mixing of the components and optimizes the slurry viscosity to ensure the final coating's rheological properties and film quality. Furthermore, the introduction of silane coupling agent KH560 enhances the interfacial bonding between the filler and the polymer matrix, improving the overall mechanical stability and adhesion performance of the coating. Under light-protected conditions, the addition of benzoin diethyl ether and HY-F-3777 fluorocarbon modified leveling agent further optimizes the leveling properties of the slurry, enabling the coating to form a uniform and smooth film on the substrate surface. Microfiltration removes any potential aggregates, ensuring the uniformity and surface quality of the final coating. Finally, a UV curing combined with hot air post-curing process is employed. Irradiation with 365 nm wavelength UV light triggers the curing reaction of the photoinitiator, rapidly forming a stable coating. The substrate temperature is controlled to suit different application requirements. Subsequent curing in a hot air environment at 80–100℃ further improves the crosslinking density and heat resistance stability of the coating, thereby ensuring the long-term stability and efficient electrothermal conversion capability of the graphene-based heating coating in heating appliances. Overall, this invention achieves a comprehensive improvement in the conductivity, adhesion, and uniformity of graphene-based heating coatings through multiple means such as solvent optimization, dispersion stabilization, interface enhancement, and curing process optimization, providing high-performance and highly reliable functional coating materials for heating appliance applications.

[0027] (3) Beneficial technical effects

[0028] 1. This invention functionalizes graphene oxide with hyperbranched polyolefin-acryloyl-POSS copolymer, thereby improving the dispersibility, interfacial bonding force and electrothermal properties of graphene. Compared with the prior art, it enhances the uniformity and conductivity of the coating, optimizes the electrothermal conversion efficiency and stability, and is suitable for high-efficiency heating coatings and intelligent thermal management.

[0029] 2. This invention improves the dispersibility and interfacial bonding of bismuth telluride nanoribbons through aminosilane modification, avoids agglomeration, and enhances the stability and thermoelectric properties of the composite material. Compared with the prior art, it enhances electrical conductivity and mechanical strength, optimizes the synergistic effect of components, and is suitable for the fields of high-efficiency thermal conductivity and electronic devices.

[0030] 3. By optimizing the solvent system, improving filler dispersibility, enhancing interfacial bonding, and employing a UV curing process, this invention achieves significant improvements in the conductivity, adhesion, and uniformity of graphene-based heating coatings. Compared to existing technologies, it exhibits higher electrothermal conversion efficiency, superior mechanical stability, and longer service life, meeting the demands of heating appliances for efficient and stable coatings. Attached Figure Description

[0031] Figure 1 The graphene-based heating coating prepared in Example 1 of this invention and its infrared spectrum during heating are shown.

[0032] Figure 2 The XRD phase analysis pattern of the surface-modified bismuth telluride nanoribbons prepared in Example 1 of this invention.

[0033] Figure 3 The image shows the morphology of the surface-modified bismuth telluride nanoribbons prepared in Example 1 of this invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0035] Example 1

[0036] A graphene-based heating coating is prepared from the following raw materials in parts by weight: 3 parts functionalized graphene, 2.5 parts surface-modified bismuth telluride nanoribbons, 2 parts polyaniline, 12 parts bisphenol A epoxy acrylate, 5 parts polyurethane acrylate, 0.5 parts benzoin diethyl ether, 0.5 parts BYK-220S dispersant, 0.3 parts HY-F-3777 fluorocarbon modified leveling agent, 1.0 part silane coupling agent KH560, 0.2 parts silicone emulsion defoamer, and 25 parts propylene glycol methyl ether acetate / N-methylpyrrolidone mixed solvent.

[0037] The preparation method of functionalized graphene is as follows: Hyperbranched polyolefin-acryloyl-POSS copolymer and graphene oxide are mixed in 80 mL of chloroform solvent at a mass ratio of 1:4 to form a mixed system. The mixed system is placed in an ultrasonic treatment device, and the ultrasonic power is controlled at 280 W for 25 min and the treatment temperature is maintained at 20 °C. Then, the ultrasonically treated mixed system is transferred to a centrifuge and centrifuged at 3800 rpm for 40 min to remove unexfoliated aggregates. The supernatant is collected to obtain a primary graphene dispersion. The primary graphene dispersion is vacuum filtered through a polytetrafluoroethylene filter membrane with a pore size of 90 nm. The deposits on the filter membrane surface are subjected to gradient washing with chloroform solvent. Each time, 45 mL of solvent is added and the washing is carried out at a stirring rate of 300 rpm for 3 min. The washing is repeated 3 times. The purified functionalized graphene powder is dried in a vacuum environment at 35 °C for 10 h to obtain functionalized graphene.

[0038] The preparation method of hyperbranched polyolefin-acryloyl-POSS copolymer is as follows: 100 parts by weight of acrylate-cage-type polysilsesquioxane, 12.0 parts by weight of 1,4-butanediol diacrylate, and 90 parts by weight of anhydrous dichloromethane are added to a Schlenk reaction flask. The system temperature is controlled at 25°C, and the mixture is stirred at 300 rpm for 30 min to form a homogeneous solution. Then, 2.2 parts by weight of α-diimide palladium are dissolved in 40 parts by weight of anhydrous dichloromethane, and the solution is injected at a rate of 0.5 mL / min using a syringe pump. The homogeneous solution was injected at a rate of n, and the ethylene pressure was maintained at 0.08 MPa. The mixture was continuously stirred and polymerized at 28 °C for 22 h. After the reaction was completed, the solvent was removed by purging with nitrogen to obtain a preliminary product. Then, 220 parts of tetrahydrofuran were added to dissolve the product, and 750 parts of methanol were added dropwise to precipitate it. After filtration, the filter cake was washed twice with 250 parts of methanol. The product was redissolved in 150 parts of tetrahydrofuran, and 500 parts of acetone were added to carry out a second precipitation. The product was then dried under vacuum at 20 °C for 70 h to obtain a hyperbranched polyolefin-acryloyl-POSS copolymer.

[0039] The preparation method of surface-modified bismuth telluride nanoribbons is as follows: 100 parts by weight of bismuth telluride nanoribbons are weighed and 200 parts by weight of deionized water are added. The mixture is dispersed for 30 min under ultrasonic power of 100 W and frequency of 35 kHz to form a uniform suspension. 5 parts by weight of α-aminopropyltriethoxysilane are added to the suspension and stirred at a magnetic stirring rate of 300 rpm for 1 h. After the reaction is completed, the suspension is centrifuged at 3000 rpm for 10 min to separate the solid and liquid. The obtained solid is washed twice with 50 parts by weight of deionized water, with a stirring rate of 200 rpm for 5 min each time. Finally, the solid is placed in a vacuum drying oven and dried at 60℃ and -0.08 MPa vacuum for 6 h to obtain surface-modified bismuth telluride nanoribbons.

[0040] The preparation method of bismuth telluride nanoribbons is as follows: 9.5 mmol of bismuth chloride dihydrate, 14.5 mmol of tellurium powder, 78 mmol of potassium hydroxide, and 29 mmol of potassium borohydride were mixed and transferred to a polytetrafluoroethylene-lined high-pressure reactor. N,N-dimethylformamide was injected to 85 wt.% of the reactor volume to form a precursor suspension. The sealed reactor was placed in a programmable oven and heated to 100 °C at a heating rate of 2 °C / min and held at that temperature for 10 h. Then, it was naturally cooled to 25 °C at a rate of 0.5 °C / min. After opening the reactor, the reaction mixture was filtered through a Buchner funnel under a vacuum of -0.08 MPa, washed three times with 50 mL of deionized water, and then washed twice with 30 mL of anhydrous ethanol. Finally, the product was dried at 75 °C and a vacuum of -0.08 MPa for 8 h to obtain bismuth telluride nanoribbons.

[0041] The bismuth telluride nanoribbons in this embodiment have an average width of 20 nm and an average length of 1 μm.

[0042] In this embodiment, the propylene glycol methyl ether acetate / N-methylpyrrolidone mixed solvent is prepared by mixing propylene glycol methyl ether acetate and N-methylpyrrolidone in a volume ratio of 30:70.

[0043] The method for preparing a graphene-based heating coating according to this embodiment includes the following steps:

[0044] S1. Add chloroform / propylene glycol methyl ether acetate mixed solvent, BYK-220S dispersant and silicone emulsion defoamer to a stirred tank, premix at 200 rpm for 10 min, control the system temperature to maintain 25±5℃, then add functionalized graphene and surface-modified bismuth telluride nanoribbons, increase the stirring speed to 800 rpm and continue for 30 min to form a primary dispersion slurry;

[0045] S2. Polyaniline, bisphenol A epoxy acrylate and polyurethane acrylate are added sequentially to the primary dispersion slurry. The mixture is treated with an ultrasonic probe at a power of 100W and a frequency of 20kHz for 30 minutes. The viscosity of the slurry at room temperature is controlled to 2000mPa·s. Silane coupling agent KH560 is then added, and the mixture is reacted at a stirring rate of 500rpm for 60 minutes under nitrogen protection to form a uniform composite slurry.

[0046] S3. Add benzoin diethyl ether and HY-F-3777 fluorocarbon modified leveling agent to the composite slurry, mix at a stirring rate of 300 rpm for 20 min under light-protected conditions, and filter online through a microfiltration membrane with a pore size of 1 μm to remove aggregates and obtain the final coating slurry.

[0047] S4. Apply the coating slurry to the surface of the substrate, transfer it to an ultraviolet curing device, irradiate it for 3 minutes at a wavelength of 365nm and a light intensity of 50mW / cm², control the substrate temperature at 45℃, and then post-cur it for 10 minutes in an 80℃ hot air circulating oven to form a graphene-based heating coating.

[0048] Depend on Figure 1 As can be seen, the infrared spectrum of the graphene-based heating coating prepared in Example 1 of the present invention shows that it has excellent heating effect, proving that the coating has good thermal response performance. Figure 2 The XRD phase analysis shown indicates that the prepared surface-modified bismuth telluride nanoribbons have a well-defined crystal structure that matches the target material, proving the success of the synthesis and the purity of the material. Figure 3 The morphological characteristics of the nanoribbon were further demonstrated, showing that it has good morphological uniformity and nanoscale structure. These results together verify the feasibility and effectiveness of Example 1 of the present invention.

[0049] Example 2

[0050] A graphene-based heating coating is prepared from the following raw materials in parts by weight: 6 parts functionalized graphene, 3.1 parts surface-modified bismuth telluride nanoribbons, 4 parts polyaniline, 19 parts bisphenol A epoxy acrylate, 8 parts polyurethane acrylate, 0.8 parts benzoin diethyl ether, 0.9 parts BYK-220S dispersant, 0.5 parts HY-F-3777 fluorocarbon modified leveling agent, 1.5 parts silane coupling agent KH560, 0.3 parts silicone emulsion defoamer, and 29 parts propylene glycol methyl ether acetate / N-methylpyrrolidone mixed solvent.

[0051] The preparation method of functionalized graphene is as follows: Hyperbranched polyolefin-acryloyl-POSS copolymer and graphene oxide are mixed in 86 mL of chloroform solvent at a mass ratio of 1:4.6 to form a mixed system. The mixed system is placed in an ultrasonic treatment device, and the ultrasonic power is controlled at 292 W for 28 min and the treatment temperature is maintained at 23℃. Then, the ultrasonically treated mixed system is transferred to a centrifuge and centrifuged at 4610 rpm for 43 min to remove unexfoliated aggregates. The supernatant is collected to obtain a primary graphene dispersion. The primary graphene dispersion is vacuum filtered through a polytetrafluoroethylene filter membrane with a pore size of 96 nm. The deposits on the filter membrane surface are subjected to gradient washing with chloroform solvent. Each time, 48 mL of solvent is added and the washing is carried out at a stirring rate of 360 rpm for 4 min. The washing is repeated 3 times. The purified functionalized graphene powder is dried in a vacuum environment at 44℃ for 15 h to obtain functionalized graphene.

[0052] The preparation method of hyperbranched polyolefin-acryloyl-POSS copolymer is as follows: 100 parts by weight of acrylate-cage-type polysilsesquioxane, 13.2 parts by weight of 1,4-butanediol diacrylate, and 96 parts by weight of anhydrous dichloromethane are added to a Schlenk reaction flask. The system temperature is controlled at 28℃, and the mixture is stirred at 360 rpm for 33 min to form a homogeneous solution. Then, 2.4 parts by weight of α-diimide palladium are dissolved in 46 parts by weight of anhydrous dichloromethane, and the solution is injected at a rate of 0.6 mL / min using a syringe pump. The homogeneous solution was injected at a rate of n, and the ethylene pressure was maintained at 0.09 MPa. The mixture was continuously stirred and polymerized at 29 °C for 23 h. After the reaction was completed, the solvent was removed by purging with nitrogen to obtain the preliminary product. Then, 238 parts of tetrahydrofuran were added to dissolve the product, and 900 parts of methanol were added dropwise to precipitate it. After filtration, the filter cake was washed twice with 325 parts of methanol. The product was redissolved in 180 parts of tetrahydrofuran, and 650 parts of acetone were added to carry out a second precipitation. The product was then dried under vacuum at 23 °C for 71 h to obtain the hyperbranched polyolefin-acryloyl-POSS copolymer.

[0053] The preparation method of surface-modified bismuth telluride nanoribbons is as follows: 100 parts by weight of bismuth telluride nanoribbons were weighed and 290 parts by weight of deionized water were added. The mixture was dispersed for 39 min under ultrasonic power of 160 W and frequency of 36.5 kHz to form a uniform suspension. 9.5 parts by weight of α-aminopropyltriethoxysilane were added to the suspension and stirred at a magnetic stirring rate of 330 rpm for 1.6 h. After the reaction was completed, the suspension was centrifuged at 4500 rpm for 13 min to separate the solid and liquid. The obtained solid was washed twice with 65 parts by weight of deionized water, with a stirring rate of 260 rpm for 6.5 min each time. Finally, the solid was placed in a vacuum drying oven and dried at 72 °C and -0.086 MPa vacuum for 7.8 h to obtain surface-modified bismuth telluride nanoribbons.

[0054] The preparation method of bismuth telluride nanoribbons is as follows: 9.8 mmol of bismuth chloride dihydrate, 14.8 mmol of tellurium powder, 79.2 mmol of potassium hydroxide, and 29.6 mmol of potassium borohydride were mixed and transferred to a polytetrafluoroethylene-lined high-pressure reactor. N,N-dimethylformamide was injected to 88 wt.% of the reactor volume to form a precursor suspension. The sealed reactor was placed in a programmable oven and heated to 124 °C at a heating rate of 2.9 °C / min and held at that temperature for 13 h. Then, it was naturally cooled to 28 °C at a rate of 0.95 °C / min. After opening the reactor, the reaction mixture was filtered through a Buchner funnel under a vacuum of -0.086 MPa, washed three times with 65 mL of deionized water, and then washed twice with 36 mL of anhydrous ethanol. Finally, the product was dried at 78 °C and a vacuum of -0.086 MPa for 9.2 h to obtain bismuth telluride nanoribbons.

[0055] The bismuth telluride nanoribbons in this embodiment have an average width of 29 nm and an average length of 3.7 μm.

[0056] In this embodiment, the propylene glycol methyl ether acetate / N-methylpyrrolidone mixed solvent is prepared by mixing propylene glycol methyl ether acetate and N-methylpyrrolidone in a volume ratio of 34.5:65.5.

[0057] The method for preparing a graphene-based heating coating according to this embodiment includes the following steps:

[0058] S1. Add chloroform / propylene glycol methyl ether acetate mixed solvent, BYK-220S dispersant and silicone emulsion defoamer to a stirred tank, premix at 260 rpm for 13 min, control the system temperature to maintain 25±5℃, then add functionalized graphene and surface-modified bismuth telluride nanoribbons, increase the stirring speed to 920 rpm and continue for 39 min to form a primary dispersion slurry;

[0059] S2. Polyaniline, bisphenol A epoxy acrylate and polyurethane acrylate are added sequentially to the primary dispersion slurry. The mixture is treated with an ultrasonic probe at a power of 160W and a frequency of 26kHz for 39 minutes. The viscosity of the slurry at room temperature is controlled to 2600mPa·s. Silane coupling agent KH560 is then added, and the mixture is reacted at a stirring rate of 590rpm for 78 minutes under nitrogen protection to form a uniform composite slurry.

[0060] S3. Add benzoin diethyl ether and HY-F-3777 fluorocarbon modified leveling agent to the composite slurry, mix at a stirring rate of 360 rpm for 26 min under light-protected conditions, and filter online through a microfiltration membrane with a pore size of 2.2 μm to remove aggregates and obtain the final coating slurry.

[0061] S4. Apply the coating slurry to the surface of the substrate, transfer it to an ultraviolet curing device, irradiate it for 4.5 min at a wavelength of 365 nm and a light intensity of 65 mW / cm², control the substrate temperature at 49.5 °C, and then post-cur it in an 86 °C hot air circulating oven for 16 min to form a graphene-based heating coating.

[0062] Example 3

[0063] A graphene-based heating coating is prepared from the following raw materials in parts by weight: 8 parts functionalized graphene, 3.7 parts surface-modified bismuth telluride nanoribbons, 6 parts polyaniline, 26 parts bisphenol A epoxy acrylate, 11 parts polyurethane acrylate, 1.1 parts benzoin diethyl ether, 1.4 parts BYK-220S dispersant, 0.6 parts HY-F-3777 fluorocarbon modified leveling agent, 1.9 parts silane coupling agent KH560, 0.4 parts silicone emulsion defoamer, and 34 parts propylene glycol methyl ether acetate / N-methylpyrrolidone mixed solvent.

[0064] The preparation method of functionalized graphene is as follows: Hyperbranched polyolefin-acryloyl-POSS copolymer and graphene oxide are mixed in 92 mL of chloroform solvent at a mass ratio of 1:5.2 to form a mixed system. The mixed system is placed in an ultrasonic treatment device, and the ultrasonic power is controlled at 304 W, the treatment time is 31 min, and the treatment temperature is maintained at 26℃. Then, the ultrasonically treated mixed system is transferred to a centrifuge and centrifuged at 5420 rpm for 46 min to remove unexfoliated aggregates. The supernatant is collected to obtain a primary graphene dispersion. The primary graphene dispersion is vacuum filtered through a polytetrafluoroethylene filter membrane with a pore size of 102 nm. The deposits on the filter membrane surface are subjected to gradient washing with chloroform solvent. Each time, 51 mL of solvent is added and the washing is carried out at a stirring rate of 420 rpm for 5 min. The washing is repeated 4 times. The purified functionalized graphene powder is dried in a vacuum environment at 53℃ for 20 h to obtain functionalized graphene.

[0065] The preparation method of hyperbranched polyolefin-acryloyl-POSS copolymer is as follows: 100 parts by weight of acrylate-cage-type polysilsesquioxane, 14.4 parts by weight of 1,4-butanediol diacrylate, and 102 parts by weight of anhydrous dichloromethane are added to a Schlenk reaction flask. The system temperature is controlled at 31℃, and the mixture is stirred at 420 rpm for 36 min to form a homogeneous solution. Then, 2.6 parts by weight of α-diimide palladium are dissolved in 52 parts by weight of anhydrous dichloromethane, and the solution is injected at a rate of 0.8 mL / min using a syringe pump. The homogeneous solution was injected at a rate of n, and the ethylene pressure was maintained at 0.10 MPa. The mixture was continuously stirred and polymerized at 30°C for 24 h. After the reaction was completed, the solvent was removed by nitrogen purging to obtain the preliminary product. Then, 256 parts of tetrahydrofuran were added to dissolve the product, and 1050 parts of methanol were added dropwise to precipitate it. After filtration, the filter cake was washed three times with 400 parts of methanol. The product was redissolved in 210 parts of tetrahydrofuran, and 800 parts of acetone were added to carry out a second precipitation. The product was then dried under vacuum at 26°C for 72 h to obtain the hyperbranched polyolefin-acryloyl-POSS copolymer.

[0066] The preparation method of surface-modified bismuth telluride nanoribbons is as follows: 100 parts by weight of bismuth telluride nanoribbons were weighed and 380 parts by weight of deionized water were added. The mixture was dispersed for 48 min under ultrasonic power of 220 W and frequency of 38 kHz to form a uniform suspension. 14 parts by weight of 1-aminopropyltriethoxysilane were added to the suspension and stirred at a magnetic stirring rate of 360 rpm for 2.2 h. After the reaction was completed, the suspension was centrifuged at 6000 rpm for 16 min to separate the solid and liquid. The obtained solid was washed three times with 80 parts by weight of deionized water, with a stirring rate of 320 rpm for 8 min each time. Finally, the solid was placed in a vacuum drying oven and dried at 84℃ and -0.092 MPa vacuum for 9.6 h to obtain surface-modified bismuth telluride nanoribbons.

[0067] The preparation method of bismuth telluride nanoribbons is as follows: 10.1 mmol of bismuth chloride dihydrate, 15.1 mmol of tellurium powder, 80.4 mmol of potassium hydroxide, and 30.2 mmol of potassium borohydride were mixed and transferred to a polytetrafluoroethylene-lined high-pressure reactor. N,N-dimethylformamide was injected to 91 wt.% of the reactor volume to form a precursor suspension. The sealed reactor was placed in a programmable oven and heated to 148 °C at a heating rate of 3.8 °C / min and held at that temperature for 16 h. Then, it was naturally cooled to 31 °C at a rate of 1.4 °C / min. After opening the reactor, the reaction mixture was filtered through a Buchner funnel under a vacuum of -0.092 MPa, washed four times with 80 mL of deionized water, and then washed three times with 42 mL of anhydrous ethanol. Finally, the product was dried at 81 °C and a vacuum of -0.092 MPa for 10.4 h to obtain bismuth telluride nanoribbons.

[0068] The bismuth telluride nanoribbons in this embodiment have an average width of 38 nm and an average length of 6.4 μm.

[0069] The propylene glycol methyl ether acetate / N-methylpyrrolidone mixed solvent in the example is a mixture of propylene glycol methyl ether acetic anhydride and N-methylpyrrolidone in a volume ratio of 39:61.

[0070] The method for preparing a graphene-based heating coating according to this embodiment includes the following steps:

[0071] S1. Add chloroform / propylene glycol methyl ether acetate mixed solvent, BYK-220S dispersant and silicone emulsion defoamer to a stirred tank, premix at 320 rpm for 16 min, control the system temperature to maintain 25±5℃, then add functionalized graphene and surface-modified bismuth telluride nanoribbons, increase the stirring speed to 1040 rpm and continue for 48 min to form a primary dispersion slurry;

[0072] S2. Polyaniline, bisphenol A epoxy acrylate and polyurethane acrylate are added sequentially to the primary dispersion slurry. The mixture is treated with an ultrasonic probe at a power of 220W and a frequency of 32kHz for 48 minutes. The viscosity of the slurry at room temperature is controlled to 3200mPa·s. Silane coupling agent KH560 is then added, and the mixture is reacted at a stirring rate of 680rpm for 96 minutes under nitrogen protection to form a uniform composite slurry.

[0073] S3. Add benzoin diethyl ether and HY-F-3777 fluorocarbon modified leveling agent to the composite slurry, mix at a stirring rate of 420 rpm for 32 min under light-protected conditions, and filter online through a microfiltration membrane with a pore size of 3.4 μm to remove aggregates and obtain the final coating slurry;

[0074] S4. Apply the coating slurry to the surface of the substrate, transfer it to an ultraviolet curing device, irradiate it for 6 minutes at a wavelength of 365nm and a light intensity of 80mW / cm², control the substrate temperature at 54℃, and then post-cur it in a 92℃ hot air circulating oven for 22 minutes to form a graphene-based heating coating.

[0075] Example 4

[0076] A graphene-based heating coating is prepared from the following raw materials in parts by weight: 12 parts functionalized graphene, 4.5 parts surface-modified bismuth telluride nanoribbons, 8 parts polyaniline, 35 parts bisphenol A epoxy acrylate, 15 parts polyurethane acrylate, 1.5 parts benzoin diethyl ether, 2.0 parts BYK-220S dispersant, 0.8 parts HY-F-3777 fluorocarbon modified leveling agent, 2.5 parts silane coupling agent KH560, 0.5 parts silicone emulsion defoamer, and 40 parts propylene glycol methyl ether acetate / N-methylpyrrolidone mixed solvent.

[0077] The preparation method of functionalized graphene is as follows: Hyperbranched polyolefin-acryloyl-POSS copolymer and graphene oxide are mixed in 1:6 mass ratio and added to 100 mL of chloroform solvent to form a mixed system. The mixed system is placed in an ultrasonic treatment device, and the ultrasonic power is controlled at 320 W, the treatment time is 35 min, and the treatment temperature is maintained at 30℃. Then, the ultrasonically treated mixed system is transferred to a centrifuge and centrifuged at 6500 rpm for 50 min to remove unexfoliated aggregates. The supernatant is collected to obtain a primary graphene dispersion. The primary graphene dispersion is vacuum filtered through a polytetrafluoroethylene filter membrane with a pore size of 110 nm. The deposits on the filter membrane surface are subjected to gradient washing with chloroform solvent. Each time, 55 mL of solvent is added and the washing is carried out at a stirring rate of 500 rpm for 6 min. The washing is repeated 5 times. The purified functionalized graphene powder is dried in a vacuum environment at 65℃ for 26 h to obtain functionalized graphene.

[0078] The preparation method of hyperbranched polyolefin-acryloyl-POSS copolymer is as follows: 100 parts by weight of acrylate-cage-type polysilsesquioxane, 16.0 parts by weight of 1,4-butanediol diacrylate, and 110 parts by weight of anhydrous dichloromethane are added to a Schlenk reaction flask. The system temperature is controlled at 35℃, and the mixture is stirred at 500 rpm for 40 min to form a homogeneous solution. Then, 2.8 parts by weight of α-diimide palladium are dissolved in 60 parts by weight of anhydrous dichloromethane, and the solution is injected via a syringe pump at 1.0 mL / min. The homogeneous solution was injected at a rate maintaining an ethylene pressure of 0.12 MPa, and the polymerization was carried out at 32 °C with continuous stirring for 26 h. After the reaction was completed, the solvent was removed by purging with nitrogen to obtain a preliminary product. Then, 280 parts of tetrahydrofuran were added to dissolve the product, and 1250 parts of methanol were added dropwise to precipitate it. After filtration, the filter cake was washed three times with 500 parts of methanol. The product was redissolved in 250 parts of tetrahydrofuran, and 1000 parts of acetone were added to carry out a second precipitation. After vacuum drying at 30 °C for 74 h, hyperbranched polyolefin-acryloyl-POSS copolymer was obtained.

[0079] The preparation method of surface-modified bismuth telluride nanoribbons is as follows: 100 parts by weight of bismuth telluride nanoribbons were weighed and 500 parts by weight of deionized water were added. The mixture was dispersed for 60 min under ultrasonic power of 300 W and frequency of 40 kHz to form a uniform suspension. 20 parts by weight of α-aminopropyltriethoxysilane were added to the suspension and stirred at a magnetic stirring rate of 400 rpm for 3 h. After the reaction was completed, the suspension was centrifuged at 8000 rpm for 20 min to separate the solid and liquid. The obtained solid was washed three times with 100 parts by weight of deionized water, with a stirring rate of 400 rpm for 10 min each time. Finally, the solid was placed in a vacuum drying oven and dried at 100℃ and -0.10 MPa vacuum for 12 h to obtain surface-modified bismuth telluride nanoribbons.

[0080] The preparation method of bismuth telluride nanoribbons is as follows: 10.5 mmol of bismuth chloride dihydrate, 15.5 mmol of tellurium powder, 82 mmol of potassium hydroxide and 31 mmol of potassium borohydride were mixed and transferred to a polytetrafluoroethylene-lined high-pressure reactor. N,N-dimethylformamide was injected to 95 wt.% of the reactor volume to form a precursor suspension. The sealed reactor was placed in a programmable oven and heated to 180 °C at a heating rate of 5 °C / min and held at that temperature for 20 h. Then, it was naturally cooled to 35 °C at a rate of 2.0 °C / min. After opening the reactor, the reaction mixture was filtered through a Buchner funnel under a vacuum of -0.10 MPa, washed five times with 100 mL of deionized water, and then washed three times with 50 mL of anhydrous ethanol. Finally, the product was dried at 85 °C and a vacuum of -0.10 MPa for 12 h to obtain bismuth telluride nanoribbons.

[0081] The bismuth telluride nanoribbons in this embodiment have an average width of 50 nm and an average length of 10 μm.

[0082] In this embodiment, the propylene glycol methyl ether acetate / N-methylpyrrolidone mixed solvent is prepared by mixing propylene glycol methyl ether acetate and N-methylpyrrolidone in a volume ratio of 45:55.

[0083] The method for preparing a graphene-based heating coating according to this embodiment includes the following steps:

[0084] S1. Add chloroform / propylene glycol methyl ether acetate mixed solvent, BYK-220S dispersant and silicone emulsion defoamer to a stirred tank, premix at 400 rpm for 20 min, control the system temperature to maintain 25±5℃, then add functionalized graphene and surface-modified bismuth telluride nanoribbons, increase the stirring speed to 1200 rpm and continue for 60 min to form a primary dispersion slurry;

[0085] S2. Add polyaniline, bisphenol A epoxy acrylate and polyurethane acrylate sequentially to the primary dispersion slurry. Use an ultrasonic probe at a power of 300W and a frequency of 40kHz for 60min to treat the slurry. Control the viscosity of the slurry at room temperature to 4000mPa·s. Continue to add silane coupling agent KH560 and react at a stirring rate of 800rpm for 120min under nitrogen protection to form a uniform composite slurry.

[0086] S3. Add benzoin diethyl ether and HY-F-3777 fluorocarbon modified leveling agent to the composite slurry, mix at a stirring rate of 500 rpm for 40 min under light-protected conditions, and filter online through a microfiltration membrane with a pore size of 5 μm to remove aggregates and obtain the final coating slurry.

[0087] S4. Apply the coating slurry to the surface of the substrate, transfer it to an ultraviolet curing device, irradiate it for 8 minutes at a wavelength of 365nm and a light intensity of 100mW / cm², control the substrate temperature at 60℃, and then post-cur it for 30 minutes in a 100℃ hot air circulating oven to form a graphene-based heating coating.

[0088] Comparative Example 1

[0089] It is basically the same as Example 1, except that hyperbranched polyolefin-acryloyl-POSS copolymer functionalized graphene is not used, but raw graphene oxide is used directly.

[0090] Comparative Example 2

[0091] The results are basically the same as in Example 1, except that the bismuth telluride nanoribbons were not modified with aminosilane.

[0092] Comparative Example 3

[0093] It is basically the same as Example 1, except that BYK-220S dispersant was not used.

[0094] Comparative Example 4

[0095] It is basically the same as Example 1, except that the silane coupling agent KH560 was not used.

[0096] Comparative Example 5

[0097] It is basically the same as Example 1, except that the light exposure time in the UV curing stage is shortened to less than 1 minute.

[0098] Comparative Example 6

[0099] It is basically the same as Example 1, except that no silicone emulsion defoamer was used.

[0100] Comparative Example 7

[0101] It is basically the same as Example 1, except that BYK-220S dispersant was not used.

[0102] Comparative Example 8

[0103] It is basically the same as Example 1, except that functionalized graphene is not used.

[0104] Comparative Example 9

[0105] It is basically the same as Example 1, except that surface-modified bismuth telluride nanoribbons were not used.

[0106] Performance testing:

[0107] Adhesion Test: The adhesion of the coating was tested using the cross-cut test according to ASTM D3359 standard. A standard grid pattern was cut on the coating surface using a multi-bladed cutting blade, and high-adhesion tape was applied and then quickly peeled off. The peeling was observed, and the adhesion was evaluated according to the standard grade. Higher adhesion indicates that the coating is firmly bonded to the substrate and is not easily peeled off.

[0108] Resistivity and Seebeck Coefficient Testing: Volume resistivity and surface resistivity of the coating were measured using the four-probe method according to ASTM D257. Coatings of different thicknesses were tested under constant temperature and humidity conditions, and their conductivity was calculated to evaluate the impact of functionalized graphene and surface-modified bismuth telluride nanoribbons on the conductive network of the coating. The thermoelectric properties of the coating were determined using a simultaneous Seebeck coefficient and conductivity testing system. The Seebeck coefficient was measured within a temperature range from room temperature to high temperatures (e.g., 25℃ to 300℃) by setting temperature differences (e.g., ΔT = 10K, 20K).

[0109] Thermal stability test: According to ASTM D2485 standard, the coating sample is placed in a high-temperature oven and heated continuously at a set temperature (such as 150℃, 200℃, 250℃) for a certain period of time (such as 24h or 48h). Then, the changes in the appearance of the coating are observed, including color, cracks, blistering and peeling, to evaluate the thermal stability under high temperature environment.

[0110] Thermal cycling test: According to IEC 60068-2-14 standard, the coating sample is cycled between -40℃ and 200℃ a certain number of times (e.g., 500 cycles). Each cycle includes rapid heating, isothermal holding, rapid cooling and isothermal holding. The coating is observed to see if cracks, peeling or performance degradation occur in order to evaluate its thermal shock resistance.

[0111] The performance of the coatings in Examples 1-4 and Comparative Examples 1-9 is summarized in Table 1.

[0112] Table 1. Performance summary of coatings from Examples 1-4 and Comparative Examples 1-9

[0113]

[0114] As shown in Table 1, the absence of functionalized graphene leads to conductive network breakage, significantly increasing resistivity, decreasing Seebeck coefficient, and reducing adhesion, further affecting heat resistance and thermal cycling performance, making the coating prone to failure. Unmodified bismuth telluride nanoribbons weaken interfacial bonding, causing uneven filler dispersion in the matrix, resulting in increased resistivity, decreased Seebeck coefficient, and reduced heat resistance and thermal cycling stability, easily leading to cracking or peeling. The absence of dispersant causes filler agglomeration, resulting in an uneven conductive network, thereby increasing resistivity and decreasing Seebeck coefficient, while also reducing adhesion and worsening the overall stability of the coating. The absence of silane coupling agent further reduces interfacial bonding, leading to weak bonding between the filler and the matrix, increasing resistivity, decreasing Seebeck coefficient, and weakening heat resistance and thermal cycling performance, making the coating prone to peeling or cracking. Insufficient UV curing time leads to decreased crosslinking density, thus affecting heat resistance and mechanical properties; although the Seebeck coefficient is slightly lower, the short-term conductivity is still close to that of the example. Without defoamers, micropores form within the coating, causing stress concentration and a slight decrease in adhesion. While short-term conductivity is not significantly affected, long-term thermal cycling life is reduced. Without functionalized graphene, the conductive network is most severely damaged, resistivity increases dramatically, Seebeck coefficient decreases significantly, and heat resistance and thermal cycling performance are the worst, making the coating highly susceptible to cracking and accelerated failure. Without modified bismuth telluride nanoribbons, interfacial bonding is reduced, making fillers prone to agglomeration in the matrix, leading to increased resistivity, decreased Seebeck coefficient, and weakened heat resistance and thermal cycling performance, making the coating more prone to peeling or aging failure.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that any equivalent structural transformations made under the concept of the present invention and using the contents of the specification and drawings of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A graphene-based heating coating, characterized in that, It is prepared from the following raw materials in parts by weight: 3-12 parts of functionalized graphene, 2.5-4.5 parts of surface-modified bismuth telluride nanoribbons, 2-8 parts of polyaniline, 12-35 parts of bisphenol A epoxy acrylate, 5-15 parts of polyurethane acrylate, 0.5-1.5 parts of benzoin diethyl ether, 0.5-2.0 parts of BYK-220S dispersant, 0.3-0.8 parts of HY-F-3777 fluorocarbon modified leveling agent, 1.0-2.5 parts of silane coupling agent KH560, 0.2-0.5 parts of silicone emulsion defoamer, and 25-40 parts of propylene glycol methyl ether acetate / N-methylpyrrolidone mixed solvent; The functionalized graphene is prepared by mixing hyperbranched polyolefin-acryloyl-POSS copolymer and graphene oxide in chloroform solvent, followed by ultrasonic exfoliation, centrifugation, vacuum filtration, gradient washing and vacuum drying. The hyperbranched polyolefin-acryloyl-POSS copolymer is prepared by catalytic polymerization, solvent precipitation, filtration and vacuum drying of acrylate-cage polysilsesquioxane, 1,4-butanediol diacrylate and anhydrous dichloromethane in a Schlenk reaction system. The surface-modified bismuth telluride nanoribbons are prepared by ultrasonically dispersing bismuth telluride nanoribbons in deionized water, adding aminopropyltriethoxysilane for surface modification, and then magnetically stirring, centrifuging, washing with deionized water and vacuum drying.

2. The graphene-based heating coating as described in claim 1, characterized in that, The preparation method of the functionalized graphene is as follows: Hyperbranched polyolefin-acryloyl-POSS copolymer and graphene oxide are mixed in a mass ratio of 1:(4~6) and added to 80~100 mL of chloroform solvent to form a mixed system. The mixed system is placed in an ultrasonic treatment device, with the ultrasonic power controlled at 280~320 W, the treatment time at 25~35 min, and the treatment temperature maintained at 20~30℃. The ultrasonically treated mixed system is then transferred to a centrifuge and centrifuged at 3800~6500 rpm for 40~50 min to remove unexfoliated aggregates. The supernatant is collected to obtain a primary graphene dispersion. The primary graphene dispersion is then vacuum filtered through a polytetrafluoroethylene (PTFE) filter membrane with a pore size of 90~110 nm. The deposits on the filter membrane surface are subjected to gradient washing with chloroform solvent, with 45~55 mL of solvent added each time and 300~500 mL added at different rates. Wash the graphene powder by stirring at rpm for 3-6 minutes, repeat the washing process 3-5 times, and then dry the purified functionalized graphene powder in a vacuum environment at 35-65℃ for 10-26 hours to obtain functionalized graphene.

3. The graphene-based heating coating as described in claim 2, characterized in that, The preparation method of the hyperbranched polyolefin-acryloyl-POSS copolymer is as follows: 100 parts by weight of acrylate-cage-type polysilsesquioxane, 12.0-16.0 parts by weight of 1,4-butanediol diacrylate, and 90-110 parts by weight of anhydrous dichloromethane are added to a Schlenk reaction flask. The system temperature is controlled at 25-35°C, and the mixture is stirred at 300-500 rpm for 30-40 min to form a homogeneous solution. Then, 2.2-2.8 parts by weight of α-diimide palladium are dissolved in 40-60 parts by weight of anhydrous dichloromethane, and injected into the homogeneous solution via a syringe pump at a rate of 0.5-1.0 mL / min, maintaining an ethylene pressure of 0.08-0.

12. The polymer was stirred at 28-32℃ for 22-26 hours under MPa for 28-32℃. After the reaction was completed, the solvent was removed by nitrogen purging to obtain a preliminary product. Then, 220-280 parts of tetrahydrofuran were added to dissolve the product, and 750-1250 parts of methanol were added dropwise to precipitate the product. After filtration, the filter cake was washed 2-3 times with 250-500 parts of methanol. The product was redissolved in 150-250 parts of tetrahydrofuran, and 500-1000 parts of acetone were added for secondary precipitation. The product was then vacuum dried at 20-30℃ for 70-74 hours to obtain a hyperbranched polyolefin-acryloyl-POSS copolymer.

4. The graphene-based heating coating as described in claim 1, characterized in that, The preparation method of the surface-modified bismuth telluride nanoribbons is as follows: 100 parts by weight of bismuth telluride nanoribbons are weighed and 200-500 parts by weight of deionized water are added. The mixture is dispersed for 30-60 minutes under ultrasonic power of 100-300 W and frequency of 35-40 kHz to form a uniform suspension. 5-20 parts by weight of aminopropyltriethoxysilane are added to the suspension, and the mixture is stirred at a magnetic stirring rate of 300-400 rpm for 1-3 hours. After the reaction is complete, the suspension is centrifuged at 3000-8000 rpm for 10-20 minutes to separate the solid and liquid phases. The obtained solid is washed repeatedly with 50-100 parts by weight of deionized water 2-3 times, with each washing being at a stirring rate of 200-400 rpm for 5-10 minutes. Finally, the solid is placed in a vacuum drying oven and dried at a temperature of 60-100℃ and a pressure of -0.08 to -0.

10. Surface-modified bismuth telluride nanoribbons were obtained by drying under a vacuum of MPa for 6-12 hours.

5. The graphene-based heating coating as described in claim 4, characterized in that, The preparation method of the bismuth telluride nanoribbons is as follows: 9.5-10.5 mmol of bismuth chloride dihydrate, 14.5-15.5 mmol of tellurium powder, 78-82 mmol of potassium hydroxide, and 29-31 mmol of potassium borohydride are mixed and transferred to a polytetrafluoroethylene-lined high-pressure reactor. N,N-dimethylformamide is injected to 85-95 wt.% of the reactor volume to form a precursor suspension. The sealed reactor is placed in a programmable oven and heated to 100-180℃ at a heating rate of 2-5℃ / min and held at that temperature for 10-20 h. Then, it is naturally cooled to 25-35℃ at a rate of 0.5-2.0℃ / min. After opening the reactor, the reaction mixture is filtered through a Buchner funnel under a vacuum of -0.08 to -0.10 MPa, washed repeatedly with 50-100 mL of deionized water 3-5 times, and then filtered with 30-50 mL of deionized water. The product was washed 2-3 times with anhydrous ethanol. Finally, the product was dried at 75-85℃ and -0.08--0.10 MPa for 8-12 hours to obtain bismuth telluride nanoribbons.

6. The graphene-based heating coating as described in claim 1, characterized in that, The bismuth telluride nanoribbons have an average width of 20-50 nm and an average length of 1-10 μm.

7. The graphene-based heating coating as described in claim 1, characterized in that, The propylene glycol methyl ether acetate / N-methylpyrrolidone mixed solvent is prepared by mixing propylene glycol methyl ether acetate and N-methylpyrrolidone in a volume ratio of (30~45):(55~70).

8. A method for preparing a graphene-based heat-conducting coating as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Add propylene glycol methyl ether acetate / N-methylpyrrolidone mixed solvent, BYK-220S dispersant and silicone emulsion defoamer to a stirred tank, premix at a stirring rate of 200~400 rpm for 10~20 min, control the system temperature to maintain 25±5℃, then add functionalized graphene and surface-modified bismuth telluride nanoribbons, increase the stirring rate to 800~1200 rpm and continue for 30~60 min to form a primary dispersion slurry; S2. Add polyaniline, bisphenol A epoxy acrylate and polyurethane acrylate sequentially to the primary dispersion slurry. Use an ultrasonic probe at a power of 100~300 W and a frequency of 20~40 kHz for 30~60 min. Control the viscosity of the slurry at room temperature to 2000~4000 mPa·s. Continue to add silane coupling agent KH560. React under nitrogen protection at a stirring rate of 500~800 rpm for 60~120 min to form a uniform composite slurry. S3. Add benzoin diethyl ether and HY-F-3777 fluorocarbon modified leveling agent to the composite slurry, mix at a stirring rate of 300~500 rpm for 20~40 min under light-protected conditions, and filter online through a microfiltration membrane with a pore size of 1~5 μm to remove aggregates and obtain the final coating slurry; S4. Apply the coating slurry to the surface of the substrate, transfer it to an ultraviolet curing device, irradiate it for 3-8 minutes at a wavelength of 365 nm and a light intensity of 50-100 mW / cm², control the substrate temperature at 45-60℃, and then cure it in a hot air circulating oven at 80-100℃ for 10-30 minutes to form a graphene-based heating coating.

9. The application of a graphene-based heating coating as described in any one of claims 1-7 or a graphene-based heating coating prepared by the preparation method described in claim 8 in a heating appliance.

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